ROO-3106: Spring Roo doesn't support new Java 7 language features

Added new implementation to utilize the antlr-java-parser library.  This may
eventually replace javaparser.
ROO-3106: Spring Roo doesn't support new Java 7 language features

Updated with changes from the classpath-javaparser project on master.
Merge pull request #21 from mikedehaan/ROO-3106-support-for-jdk7

ROO-3106: Spring Roo doesn't support new Java 7 language features